Chapter 29 - Oral cavity Flashcards
Which system of dental nomenclature is used in equine dentistry?
The modified Triadan system
How long can the reserve crowns of equine cheek teeth be?
Less than 10 cm
How many roots do mature maxillary cheek teeth typically have?
Three roots
How many roots do mandibular cheek teeth usually have?
Two roots (rostral and caudal roots)
How many pulp horns do the Triadan 08 to 10 cheek teeth have?
Five pulp horns
How many pulp horns do the Triadan 06 and 11 cheek teeth have?
Six pulp horns for T06 and the seven pulps for T11
What dental structure is present in maxillary cheek teeth but absent in mandibular cheek teeth?
Infundibulae
What percentage of infundibulae are incompletely filled with cement?
90%
What condition can result from incompletely filled infundibulae?
Caries
Which are the central cheek teeth?
Triadan 08s to 10s that are rectangular on cross section and have 5 pulp horns
Figure 29-3. Identification of the individual pulp chambers of mature equine cheek teeth using a recently modified system of pulp nomenclature by du Toit et al.4 The 06s (left side of figure) have six pulp horns. The 07s to 10s (center of figure) have five pulp horns. The 11s (right side of figure) have six or seven horns.
Figure
What happens to the maxillary cheek teeth have 2 infundibulae that in 90% are incompletly filled with normal cement?
later develop
caries that can lead to more significant disease (Figure 29-5)
Do mandibular cheek teeth have infundibulae?
No however some infoldings of peripherial cement can give the appearance of such (figure 29-6)
Figure 29-1. The modified Triadan system of equine dental nomenclature.
To identify deciduous teeth, add 4 to the first number of its permanent
successor. For example, the deciduous incisor 501 is replaced by permanent
incisor 101.
Figure 29-2. Partially dissected left side of the head of a young adult horse showing the great length of the cheek teeth reserve crowns that have now developed roots (enamel-free areas) on their apical aspects. The relationships of the four caudal upper cheek teeth to the maxillary sinuses is apparent in this dissection, as is the angulation of the caudal and rostral cheek teeth that keeps the occlusal aspect of all cheek teeth in tight contact.
Figure 29-4. Diagram of a longitudinal section in the sagittal plane of a young maxillary cheek tooth, with normal curvature, showing both infundibulae filled with cement. The pulp horns usually extend to about 10 mm beneath the occlusal surface. Note that the occlusal surface is a sandwich of cementum, dentine, and enamel, with the harder enamel ridges protruding on the occlusal surface.
Figure 29-5. Cross section of a maxillary cheek tooth (Triadan 07-10 position) showing the five numbered pulp horns (P1 to P5), rostral infundibulum (RI), and caudal infundibulum (CI). As is often the case, the rostral infundibulum is incompletely filled with cementum and may later develop caries.
How frequently should horses in certain performance disciplines (e.g., dressage) have dental exams?
At least every 6 months.
Figure 29-6. Diagram of a longitudinal section in the sagittal plane of a young mandibular cheek tooth showing the common pulp chamber and some individual pulp canals that contain the pulp horns. Mandibular cheek teeth do not contain infundibulae, but have deeply infolded peripheral cementum that can resemble infundibulae
What symptoms can indicate possible dental disease during an external exam?
Swelling of the mandible or maxilla and identification of draining tracts.
What should be suspected in horses with unilateral nasal discharge and ipsilateral lymphadenitis?
Dental disease.
What are indicators of dental sinusitis?
Occlusal pulpar exposure or a midline sagittal fracture through the infundibulae.
Indications of oral pain
Evidence of weight loss and observation of
slow mastication, abnormal masticatory movements, or quidding
(dropping partly masticated food from the mouth)
How to perform dental exam
To assess jaw mobility, the rostral aspect of the mandible should be pushed sideways with the mouth closed and the distance of lateral movement of the lower incisors in relation to their upper counterparts
Palpation through the cheeks
A useful test for suspected cases of dental disease is to feed the (unsedated) horse a small amount of forage
What can block the lateral movement of the mandible during jaw mobility assessment?
Major cheek tooth overgrowths.
What tools are essential for a thorough visual examination of equine cheek teeth?
A full mouth speculum, headlight, and mirror or oral endoscope.
What dental condition can be detected by palpation through the cheeks?
Food pocketing, displaced or missing teeth, or overgrowths.
What can a pain response during cheek palpation suggest?
Buccal ulceration or dental fractures.
What solution can be used to flush food from the oral cavity during dental exams?
Water or a 0.1% chlorhexidine solution.
What should be examined to detect pulpar exposure or dental fractures?
The occlusal surfaces of each cheek tooth.
What percentage of infected mandibular cheek teeth show pulpar exposure?
34%
What percentage of infected maxillary cheek teeth show pulpar exposure?
23%.
What tool is used to assess pulpar exposure on the occlusal surface of cheek teeth?
A fine steel probe.
What type of neoplasia can originate on the hard palate and be detected during oral examination?
Sinus carcinoma.
What is the correct term for a rostral projection of the upper incisors beyond the lower incisors in a horizontal plane?
Overjet.
What term describes the upper incisors growing down in front of the lower incisors in a vertical direction?
Overbite.
Which condition refers to a shortness of the mandible?
Mandibular brachygnathism.
What is a potential consequence of overjet and overbite in older horses?
Overgrowth of upper incisors, resulting in a “smile.”
What treatment is used to correct overjet in foals?
Incisor orthodontic brace with steel wires.
At what age is the tension band surgery best performed in foals?
Around 3 months of age up to 8 months of age
What condition may worsen overbite if only an orthodontic brace is used?
Caudo-ventral deviation of the upper incisors and incisive bone.
What device is used in conjunction with an orthodontic brace to treat overbite?
Biteplate (2-4 mm thick)
What can be used to attach a biteplate to the teeth?
Polymethyl methacrylate (PMMA).
What problem may arise when a foal with a biteplate is nursing from its dam?
The biteplate may hurt the mare’s udder.
What should be done if a foal is uncomfortable with the brace?
Administer NSAIDs and antigastric ulcer medication, such as omeprazole.
Overjet The wires are fixed around the caudal aspect of which teeth?
caudal aspect of the 507 and 607 (deciduous third premolar) to retard growth of the incisive bone (premaxilla) and maxilla
Which product promotes reparative tertiary dentine formation?
Calcium hydroxide or mineral trioxide aggregate (MTA) pulp dressing
What new tx is available for active lengthening of the mandibular bodie?
A newer technique involves active lengthening (mandibular osteodistraction) of the mandibular bodies following osteotomies and bilateral implantation of a ratchet device - chapter 104
What age is ideal for overjet correction with tension bands?
Tension band surgery is best performed at around 3 months of age, but it can be of value in foals up to 8 months old.
Describe the first skin incision to place the wiere between 07 and 08s
A 1-cm horizontal incision is made in the skin of the cheeks as dorsally as possible to avoid damaging the dorsal buccal branch, opposite the interdental spaces between the upper 07s and 08s. A short Steinmann pin fitted to a Jacobs chuck or 2.5 mm dental drill can be pushed through the skin wound to puncture the cheeks and enter the oral cavity (Figure 29-10). Using a finger in the oral cavity for guidance, the point of the pin or drill is directed into the interdental (interproximal) space as close to the gingival margin as possible, and it is subsequently forcibly pushed (while twisting) through this tight space and directed dorsomedially to exit at the medial (palatal) interdental space, again close to the gingiva (at the border of the hard palate). The Steinmann pin is withdrawn and a 14-gauge needle is inserted along its path, followed by insertion of a 1.25-mm diameter stainless-steel wire of 60 cm in length through the needle into the interdental space and into the oral cavity. The external free end of the wire is now directed through the buccal incision into the oral cavity, directly adjacent to the initially passed part of the wire,
What can occur as complication of the buccal horizontal incision if not made as dorsal as possible?
If you do not avoid the avoid damaging the dorsal buccal branch, temporary neuropraxia of buccal branches of the facial nerve or hematoma formation can occur following this buccal incision
The two free ends of the wire from the mouth are placed what is the next step?
The two free ends of the wire are withdrawn from the mouth on either side of the cheek teeth, making them even in length. While pulling them rostrally, the free ends are twisted together back to the rostral border of the upper 06s, as dorsally as possible. The twisted wires are then placed over the labial (vestibular) aspect of the upper incisors. The procedure is repeated on the other side of the mouth, and the free ends of both pairs of wires are twisted tightly together, just below the gingival borders of the upper incisors (or interwoven between incisors at their gingival level) and their ends are trimmed (Figure 29-12). The wire knot should be embedded in polymethyl methylacrylate (PMMA/acrylic) to prevent soft tissue trauma.
If you have overbite instead of overjet the tx of wires only will worsen the overbite. What should you add to the tx?
The biteplate can be fashioned from a perforated (2- to 4-mm thick) aluminum plate that is cut to fit the shape of the rostral aspect of the maxillary incisors and hard palate, extending caudad about 4 to 5 cm (approximately 2 in) from the incisors.
In case of overbite which overgrowths should be addressed?
Any overgrowths on the rostral aspects of the upper 06s and on the caudal aspects of the lower 08s should be rasped off, to promote free rostrocaudal mandibular movement
Orthodontic treatment is feasible in adult horses?
Orthodontic treatment is not feasible in adult horses. Large overjet/overbite incisor overgrowths in adult horses should be reduced using power or manual instruments, in stages of about 3 mm every 3 to 4 months, to prevent pulpar exposure
Prognathism (“undershot jaw” or “underbite” or sow mouth) is rare in Equidae, except in
miniature horses and donkeys, and is usually clinically insignificant
What percentage of foals in the largest study showed complete reduction of overjet?
25%.
What condition is also referred to as “sow mouth”?
Underbite (prognathism).
What are the common clinical signs of underbite in miniature horses and donkeys?
Concave occlusal surface of the upper incisors (a “frown”).
When are retained deciduous incisors usually problematic?
Deciduous incisors normally lie rostral (i.e., labial) to their permanent counterparts, are occasionally retained beyond their normal time of shedding and they usually cause the permanent incisor to be displaced caudally (lingually/palatally) leading to permanent changes in the incisor occlusal surface.
How are loose deciduous incisors extracted?
Using small-animal dental extraction forceps.
What should be done if a retained deciduous incisor is firmly attached?
Use local anesthesia and incise the surrounding tissue before extraction.
What technique is used to extract a deeply retained deciduous incisor?
Surgical extraction with elevation of a gingival flap.
What are supernumerary incisors?
Permanent teeth additional to the normal six incisors in each arcade.
What treatment is generally recommended for supernumerary incisors?
Biannual rasping of overgrown incisors, if necessary.
What is the common cause of incisor fractures in horses?
Trauma, usually from kicks.
What is a recommended treatment for young horses with exposed pulps?
Vital pulpotomy.
What material is used to fill an exposed pulp canal after cleaning?
Calcium hydroxide or mineral trioxide aggregate (MTA).
What technique is used to promote reparative tertiary dentine formation after pulp exposure?
Application of calcium hydroxide.
What abnormal incisor wear pattern is associated with crib biting?
Abnormal wear of the occlusal and rostral aspects of the 01s and occasionally the 02s.
What is the term for a tilted or slanted incisor occlusal surface?
Diagonal bite, slope mouth, or slant mouth.
What craniofacial abnormality is often associated with slant mouth?
Wry nose (campylorrhinus lateralis).
What complication can arise from pulpar exposure in older horses?
Pulpar ischemia and necrosis.
What condition describes a total lack of occlusion between upper and lower incisors?
Severe underbite (prognathism).
What dental procedure can lead to diastemata formation between cheek teeth?
Orthodontic brace treatment with rostral movement of the 07 cheek teeth.
How can you control pulpar bleeding during incisor fracture treatment?
Use compressed cotton wool or dental paper points.
What is used to improve bonding of dental restorative materials to an incisor?
40% Phosphoric acid gel.
Why should overgrowths on incisors be reduced in stages in adult horses?
To prevent pulpar exposure. 3 mm every 3 to 4 months
Figure 29-10. A bone drill and drill sleeve have been inserted through a horizontal stab incision in the skin and buccal muscles of this foal with overjet to drill between the deciduous cheek teeth for placement of a tension band prosthesis.
Figure 29-11. A piece of 1.25-mm stainless-steel wire is being inserted through the cheek incision into the interdental space between the first and second cheek teeth (606 and 607).
Figure 29-12. The twisted wires that are attached bilaterally to the cheek teeth have been interwoven between some incisors and then tightly joined together in front of the incisors, to retard incisive bone and maxilla growth
Figure 29-20. This large and rostromedially displaced “wolf tooth” (105) (arrows) has been loosened from its periodontal attachments with an elevator. The intact, loosened tooth can now be readily extracted with forceps.
Figure 29-22. A diastema burr (Powerfloat) is being used to widen the occlusal, interdental space in this specimen, which had diastema and food pocketing (arrows). A more effective technique to widen valve-shaped diastemata involves inserting the burr from the lateral and medial directions into the wider subocclusal space, followed by burring occlusally and caudally.
Figure 29-21. A diastema with deep interdental food pocketing is present between 410 and 411, both of which have slight lingual (medial) displacement. A slight overgrowth is also present on 411 (arrow), which may have caused caudal orthodontic displacement of this cheek tooth and so predisposed to the diastema.
Figure 29-23. This mandible shows a grossly bucally (laterally) displaced cheek tooth that is probably developmental in origin. Because of its angulation, the displaced cheek tooth it appears wider than its counterparts. Note the severe periodontal food pocketing in diastemata beside the displaced cheek tooth and to a lesser extent between other cheek teeth. Oral extraction of this displaced cheek tooth is indicated.
Burgess elevators used in wolf teeth extraction
Musgrave elevator used in wolf teeth extraction
Figure 29-24. Intraoral view of a horse with a lateral “slab” fracture of 208. The fracture site is filled with food that slightly displaced the larger palatal (medial) portion into the hard palate and markedly displaced the thin, buccal fragment (arrows) into the cheeks, where it caused buccal ulceration (arrowheads).
Figure 29-29. The cleaned infundibulum, which has been acid etched, washed, and dried, is having bonding material applied with a flexible brush.
Figure 29-31. Computed tomography image of a horse that recently had 209 extracted after a midline infundibular caries-related fracture and left-sided sinusitis developed. The empty alveolus is granulating well (white circle). To prevent a similar contralateral problem, a carious infundibulum in 109 has been restored (arrow). Although the apical aspect of the infundibulum has a filling defect, this restoration is anticipated to prevent fracture/apical infection for at least 5 years.
Figure 29-33. The occlusal surface of this cheek tooth (06s have six pulp horns) has intact secondary dentine over five pulp cavities, but has a pulp exposure over one (pulp horn five, with needle inserted) indicative of chronic pulpar death. Some localized caries is present in both infundibulae.
Figure 29-34. This radiograph shows an apically infected mandibular cheek tooth, with thickening of the underlying mandible that also contains a lytic track leading to its caudal root. The caudo-ventral aspect of this root has been destroyed. The probe inserted up the sinus tract further confirms that infection is present in this cheek tooth.
How is the inferior alveolar nerve anesthetized?how do you perform?
The mandibular foramen lies at the intersection of a perpendicular line drawn from the lateral canthus of the eye to the dotted line running parallel to the occlusal surface of the cheek teeth. a 15-cm (6-in), 18-gauge spinal needle is “walked” up the periosteum of the medial aspect of the mandible and 20 to 30 mL of lidocaine is deposited at the site and 1 to 2 cm dorsocaudally to i
Figure 29-35. The mandibular foramen lies at the intersection of a perpendicular line drawn from the lateral canthus of the eye to the dotted line running parallel to the occlusal surface of the cheek teeth.
Figure 29-36. A narrow-blade, cheek tooth separator is being inserted between two cheek teeth in this specimen.
Figure 29-44. This intraoperative radiograph shows the punch correctly positioned over the affected apex and also shows that it is facing in a suitable direction to effectively remove this (09) cheek tooth.
